Engines may be configured to operate with more than one fuel type. For example, engines may operate with liquid fuel, such as diesel, and gaseous fuel, such as natural gas. A mixture of gaseous fuel and air provided to a cylinder of an engine may be ignited when liquid fuel is injected into the cylinder. The compression of the cylinder ignites the liquid fuel and the gas/air mixture burns from the initiation site created by the liquid fuel combustion, forming a flame front that compresses and heats the unburned mixture ahead of the flame front. Under certain conditions where the temperature and pressure of the unburned gases reach an auto-ignition limit, combustion may be initiated before the main flame front can initiate combustion, resulting in a secondary flame front. If the secondary flame front and main flame front meet, cylinder vibrations may occur that can lead to engine degradation. Further, uncontrolled auto-ignition may result in high in-cylinder pressure, which may lead to engine degradation and potentially higher emissions due to higher in-cylinder temperatures.